EP4053348A1 - Retention assembly and building with a retention assembly - Google Patents

Abstract

Shown and described is a retention arrangement for retaining precipitation water, in particular in the event of heavy rain events in urban, densely populated built-up areas, having a porous and absorbent and/or swellable water storage material, the retention arrangement being a particularly vertical retention facade (3) and/or a particularly vertical retention wall of a structure, such as a residential or commercial building (1), an industrial hall or noise barrier or bridge or the like, or is designed as a free-standing, essentially vertical retention structure, the retention arrangement being connected to a building arrangement for draining rainwater from at least one roof and/or facade surface of the building arrangement for retention arrangement and for at least temporary storage of precipitation water in the retention arrangement, and wherein the retention arrangement for water intake and water storage tion of a minimum amount of water of 10 l/(m²h) to 50 l/(m²h), preferably of 15 l/ (m²h) to 40 l/(m²h), is designed and furnished with a floor area of the building arrangement of at least 50 m² , preferably of at least 100 m², particularly preferably of at least 200 m², and with a precipitation duration of at least 0.25 h, more preferably of at least 0.5 h, particularly preferably from 0.75 h.

Description

The invention relates to a retention arrangement for retaining precipitation water, in particular in the event of heavy rain events in urban, highly densely built-up areas. In addition, the present invention relates to a building, such as a residential or commercial building, an industrial hall, a noise barrier, a bridge or the like, with at least one retention arrangement connected to the building or freestanding.

The technical field of application of the invention is in structural engineering, especially in the area of facade surfaces of buildings, the term "building" in the context of the invention is to be interpreted broadly and the term is understood in particular as residential or commercial buildings, industrial halls, soundproof walls, bridges or the like .

Measures to retain rainwater and protect against flooding are moving into the focus of architecture, urban planning and builders, as extreme events - such as heavy rain and flooding - occur more frequently as a result of climate change.

The cities in particular are of central importance here. Due to increasing urbanization, these are characterized by a high structural density and a high degree of sealing. The high degree of sealing, the low seepage potential and increasing soil compaction amplify the consequences of heavy rain events.

There are various state-of-the-art measures in the field of rainwater retention. On the one hand, this concerns the unsealing of areas, above-ground or underground seepage measures, above-ground retention (in open water areas, ditches, retention basins, on roofs, etc.), underground retention (in cisterns, trenches, etc.) or even temporary retention on traffic areas, on green spaces and by greening roofs and planting trees. There are also direct building protection measures, such as sewer return protection or seals. In this way, different effects are achieved. On the one hand, water ingress is avoided. On the other hand, the infiltration of water is simplified, water is introduced with a delay or water is diverted.

Green roofs and retention roofs are increasingly being used in urban areas, with the latter being primarily designed to retain rainwater. The depth of the substrate and the shape of the drainage layer of retention roofs are influential factors in the water retention to be achieved. In this way, the water can be diverted over long distances and the outflow can be delayed. Many existing buildings are not suitable for a retention roof due to static requirements, because the total weight increases with increasing water storage capacity. As a rough approximation, the total weight of extensive green roofs is around 50 to 70 kg/m ² , intensive green roof gardens can reach over 1,000 kg/m ² . In heavy rain events, green roofs are a building block of an optimized urban rainwater management system in terms of retention capacity, but they can reach their limits, since the percentage of rain retention decreases with increasing precipitation intensity and the additional precipitation is then passed on directly and without delay.

In the field of urban planning and development, innovative drainage concepts are being developed worldwide. In these concepts, the seepage and drainage of rainwater is the focus of the measures. Playgrounds, sports fields and other public spaces are planned as height-staggered areas. By lowering the areas and adjusting the gradient, they serve as temporary water basins.

Such measures usually require complex and expensive construction measures. Larger areas have to be redesigned and roads have to be included. The scope for action usually relates to public areas, private land can hardly be integrated into the planning of the measures.

Measures for rainwater retention on facade surfaces can also be seen in vertical greening concepts, since plants and substrates absorb rainwater and/or use it for irrigation. In these vertically installed gardens, however, rainwater retention only takes place to a minor extent. Due to the high installation and maintenance costs, large-scale facade gardens can only be found occasionally and are then unsuitable for rainwater retention due to their high dead weight.

Such vertical gardens are usually only installed in the form of individual projects as art or advertising objects.

The object of the present invention is to provide a retention arrangement and a structure, in particular a building, with such a retention arrangement which, in a structurally simple manner and at low cost, can contribute to mitigating the consequences of heavy rain events through water absorption and storage, whereby, preferably, the retention arrangement should offer the potential for economical mass production and should be able to be used in different structural engineering areas. The retention structure should be usable and suitable in particular for an industrial implementation of the use of facade surfaces of buildings and other structures for rainwater retention. It should preferably be possible to absorb and store water without additional equipment, surrounding seals or enclosures. In addition, the retention arrangement should be designed and usable not only for water intake and storage, but also for water collection and/or water drainage. By using the retention arrangement according to the invention, the microclimate of buildings should preferably be able to be positively influenced, with humidification and cooling of the buildings in particular being possible in a simple manner.

The aforementioned objects are achieved according to the invention by a retention arrangement having the features of claim 1 and by a structure having the features of claim 14. Advantageous configurations of the invention are the subject matter of the dependent claims.

The retention arrangement according to the invention has a porous and absorbent and/or swellable water storage material, wherein the retention arrangement forms or is designed as a free-standing, essentially vertical retention structure, for example in the manner of a (sculptural) water tower, in particular with a ratio of enveloping surface area to volume of less than 5.0, preferably less than 2.5.

According to the invention, the retention arrangement is connected to a building arrangement for draining rainwater from at least one roof and/or facade surface of the building arrangement to the retention arrangement and for at least temporarily storing drained rainwater in the retention arrangement. Here, the retention arrangement can form a retention facade of the building, from the roof and/or facade surface of which rainwater is conducted to the retention arrangement. However, it is also possible for the retention arrangement to receive precipitation water from other neighboring structures, such as residential or commercial buildings, industrial halls, noise barriers or bridges or the like, via a corresponding line routing. For this purpose, the retention arrangement is fluidically connected to the building arrangement, in particular via corresponding water-carrying inlet and/or outlet lines.

According to the invention, the retention arrangement is set up and designed to feed in rainwater. The term “established and designed” is to be understood in particular as a directed and/or forced supply, preferably a controlled and/or regulated supply, of rainwater. A control and/or regulation device can be provided for the controlled and/or regulated automatic change in the amount of water that is fed to the retention arrangement in the event of heavy rain events. The retention arrangement according to the invention is thus to be distinguished from such vertical arrangements with water-storing material, such as green walls, in which incidental storage of rainwater can occur in the arrangement, but these arrangements primarily serve other purposes, such as greening buildings. For supplying precipitation water, the retention arrangement according to the invention has at least one technical device which is designed for the directed and/or forced and/or controlled and/or regulated supply of precipitation water to and/or into the retention arrangement.

It is essential to the invention that the retention arrangement is designed and set up for water absorption and water storage of a certain minimum amount of water. Since the invention relates to the retention of precipitation water during heavy rain events, the retention arrangement must be able to absorb a sufficiently large amount of water, based on a specific duration of the heavy rain event and a specific floor area of the building arrangement. In the event of rain, water should be diverted to the retention arrangement via the roof and/or facade surfaces and absorbed by the retention arrangement. In order to catch or mitigate heavy rain events, the invention proposes a retention arrangement for water absorption and water storage of a minimum water quantity of 10 l/(m ² h) to 50 l/(m ² h), preferably 15 l, based on the floor area of the building arrangement and a duration of precipitation /(m ² h) to 40 l/(m ² h), with a floor area of the building arrangement of at least 50 m ² , in particular at least 100 m ² , particularly preferably at least 200 m ² , and with a precipitation period of at least 0.25 h, more preferably at least 0.5 h, most preferably 0.75 h. For example, if the minimum water volume to be absorbed is 10 l/(m ² h), this results in an absolute water volume of 125 l for a floor area of the building arrangement of 50 m ² and a rainfall period of 0.25 h. In the example just described, the retention arrangement must therefore have at least be designed and set up to store a rain quantity of 125 l with a rain quantity of 10 l/(m ² h) for a building arrangement with a floor area of 50 m ² . With a larger floor area of the building arrangement, a correspondingly larger storage volume of the retention arrangement is to be assumed. The minimum amount of water specified according to the invention is therefore always related to a minimum floor area of the building arrangement and a minimum duration of precipitation in order to ensure that the goal of weakening the consequences of heavy rain events can be achieved by water absorption and storage in the retention arrangement according to the invention.

The "footprint" of the building arrangement is understood to mean the built-up area of the ground on which the building arrangement stands, as viewed from above, which includes roof overhangs, canopies or the like of the building arrangement. According to the invention, the base area is delimited by the contour line of the building in a plan view from above.

In a building with a floor area of 120 m ² , for example, the minimum storage volume of the retention arrangement according to the invention can be between 300 l and 3000 l, preferably between 450 l and 2400 l. However, the minimum storage volume can also be larger.

The retention arrangement according to the invention is particularly preferably designed for water absorption and water storage of a multiple of the minimum storage quantity.

$$\begin{array}{c}{\mathrm{kg}}_{\mathrm{WSM},\mathrm{tr}.}=\mathrm{Masse}\mathrm{des}\mathrm{trockenen}\mathrm{Wasserspeichermaterials}\\ \left(\mathrm{Trocknung}\mathrm{bei}105°\mathrm{C}\mathrm{für}24\mathrm{h}\right).\end{array}$$

Furthermore, the invention provides that the retention arrangement is designed and set up for water absorption of 0.1 to at least 2.0 kg _water /(kg _WSM, tr.min), preferably from 0.25 to at least 1.5 kg _water /( kg _WSM,tr .min), particularly preferably from 0.5 to at least 1.0 kg _water /(kg _WSM,tr .min),
With: $$\begin{array}{c}{\mathrm{kg}}_{\mathrm{water}}=\mathrm{from}\mathrm{to\; the}\mathrm{water\; storage\; material}\mathrm{recorded}\mathrm{water\; mass}\mathrm{in}\\ \left[\mathrm{kg}\right]\mathrm{and}\mathrm{With}\end{array}$$

$$\begin{array}{c}{\mathrm{kg}}_{\mathrm{WSM},\mathrm{tr}.}=\mathrm{Dimensions}\mathrm{of}\mathrm{dry}\mathrm{water\; storage\; material}\\ \left(\mathrm{drying}\mathrm{at}105°\mathrm{C}\mathrm{for}24\mathrm{H}\right).\end{array}$$

In this context, the mass of the dry water storage material refers to the mass after drying the water storage material at 105 °C for 24 hours.

The water absorption kinetics (FSC value, "Free Swelling Capacity") can be determined by the method of determining the water absorption with free swelling in excess liquid. In this case, a pretreatment of the water storage material by drying at 105° C. for 24 hours can be provided. A defined dry quantity of the water storage material, for example 10 g, is placed in a heat-sealable tea bag. The sample is immersed in water at 20 °C and removed after defined times, 1, 2, 5, 10, 30, 60 minutes, and the sample weight is determined in each case. The water absorption is given as a relative increase in mass corrected for the weight of the wet tea bag, with the relative increase in mass in [%] corresponding to the ratio of the mass of the water storage material after water absorption to the mass of the dry water storage material in percent, i.e. a relative increase in mass of 100% corresponds to one Doubling of the dry mass of the water storage material. To determine the uptake kinetics, uptake is assumed to be linear in the range from 0 to 5 minutes.

The kinetics of water uptake determine the ability of the retention arrangement to absorb and store a sufficiently large amount of water in a specific period of time. The retention arrangement according to the invention is set up and designed to absorb large amounts of water quickly and thus at least to mitigate the consequences of heavy rain events. The retention arrangement according to the invention thus differs from the building walls and facades known from the prior art, which consist, for example, of sand-lime brick materials and thus basically have a certain water storage capacity. However, these known building walls and facades are not set up and designed to absorb large amounts of water in a short period of time, so that in the event of heavy rain events, the heavy rain quantities flow away from such building walls and facades without mitigating heavy rain events.

Particularly preferably, the retention arrangement according to the invention can be set up and designed to take up and store a water quantity of at least 2 l/m ² , preferably at least 3 l/m ² , more preferably at least 4 l/m ² , based on a roof and/or building area of the building.

Based on the outer surface or outer skin of the retention arrangement, the water storage capacity of the retention arrangement can be at least 8 l/m ² , preferably at least 10 l/m ² , particularly preferably at least 12 l/m ² .

According to the invention, at least one feed and/or outlet opening, cavern, water-conducting structure for introducing, guiding and distributing water and/or discharging precipitation water can be provided on and/or in the retention arrangement, in particular in an area of the retention structure near the roof and/or in an area near the ground be. Thus, the retention arrangement according to the invention can be used not only for water storage and water retention but also for the production of process water and is then preferably connected or can be connected to a mains water network and/or a collection tank.

With the invention, for the first time, retention facades and/or retention walls or also free-standing, for example sculpturally designed, spatial structures are used as vertical water reservoirs for rainwater during heavy rain events, in particular in urban spaces. The retention arrangement according to the invention makes it possible to implement water retention on facade surfaces of buildings or also adjacent to such facade surfaces for water absorption and storage of rainwater with little installation and maintenance effort and low costs compared to vertical water retention concepts, such as green roofs.

Improvements and advantages generated with the invention compared to the prior art relate in particular to the development of still unused areas in the field of rainwater retention to reduce the consequences of heavy rain events such as floods, overloading of the sewer system or the like. In addition, the solution according to the invention can contribute to equalizing the inner-city competition with regard to the space requirement between housing construction and climate adaptation measures. In principle, it is possible to produce the retention arrangement economically and industrially. The retention arrangement can be used in the area of new construction measures and in the case of changes to the stock. With a suitable design of the retention arrangement, good static properties can be achieved, which allow the retention arrangement to be constructed in a modular manner, for example with curtained facades, or in the form of independent wall bodies or as free-standing elements or retention sculptures. By using suitable materials, the urban microclimate can be advantageously influenced and at the same time the possibility of extensive greening is opened up. At the same time, the retention structure can meet structural and building law requirements.

In particular, the retention structure enables water absorption and storage independently of water storage in tank-like containers within the retention wall, with the water absorption and storage capacity of the retention structure being at least essentially or completely dependent on the water storage material used and its proportion of the total amount of the retention structure. However, water storage in tank-like containers in addition to water absorption and storage in the water storage material of the retention structure is not ruled out.

Otherwise, the retention structure can be free of plant substrates and otherwise unoccupied with plants or unplanted. However, as explained above, the retention structure can also be used as a further secondary functionality as a particularly vertical greening concept, in which case corresponding areas of the retention structure can then be provided for receiving plants and for supplying nutrients to the plants.

The invention particularly preferably provides for a direct or indirect connection of the retention arrangement according to the invention to a roof and/or building drainage system with corresponding collection and conduit devices for rainwater, so that rainwater occurring in the area of the building roof and/or the building facade is collected and diverted to the retention arrangement can.

In addition and/or alternatively, an indirect connection of the retention arrangement according to the invention to a storage tank can also be provided, in which rainwater that accumulates on the roof and/or building surfaces is collected. The storage tank is then connected to the roof and/or building drainage system and can be located anywhere, even at a distance from the building. Precipitation water can then be fed from the storage tank to the retention arrangement according to the invention, in particular via a pump or also via wick structures with capillary action.

It is also possible to connect the retention arrangement according to the invention to a collection container below normal level, for example to underground tanks or to a septic tank, or also to other precipitation retention and/or collection basins. A use of the retention arrangement for flood protection is also not ruled out, in which case the retention arrangement can be designed and set up to draw in water from the subsoil and/or to store flood water. The supply of high water to the retention arrangement can take place, for example, via pumps and/or wick structures with capillary action.

In addition, the retention facility can be used to store water in arid areas.

In addition, the retention arrangement according to the invention can be set up and designed for feeding in mains water from a mains water network.

The structure according to the invention, such as a residential or commercial building, industrial hall, noise protection wall, bridge or the like, has at least one retention arrangement of the type according to the invention which is connected to the structure or is free-standing, with the retention arrangement preferably being attached to a precipitation collection surface of the structure, in particular to a roof and/or building drainage of the structure, and/or connected and/or connectable to a mains water network.

In addition, it is possible that the retention arrangement or the structure is and/or can be connected to an external water reservoir, i.e. a water reservoir that is separate from the structure.

More preferably, the retention arrangement is firmly connected to the structure and/or forms a particularly load-bearing part of the structure.

The retention arrangement according to the invention can be provided on at least one side of the structure, preferably on at least two opposite sides of the structure, in particular in structures arranged in a structure, such as terraced houses, more preferably on all sides of the structure, in particular in free-standing structures such as single-family houses.

In a preferred embodiment of the invention, at least part of a building facade is formed by the retention arrangement. The retention arrangement can be hung in front of and/or in front of a building facade. The retention arrangement can be connected to a building wall of a building as a curtain wall, in particular in a modular design. Thus, the retention arrangement according to the invention as a so-called "retention facade" can form at least a part of the outer shell of the building, in particular the predominant part, more particularly the entire outer shell. A "façade" in the sense of the invention is the visible shell (building shell or outer skin) of the structure, with the exception of roof surfaces and open spaces as well as window surfaces, door surfaces, supply lines, derivations, balconies or the like.

mit

• m _Wasser: zu speichernde Wassermenge [kg]
• F _Total: totale (gesamte) Fassadenfläche des Gebäudes [m²]
• S: Stärke/Dicke [m] der Retentionsfassade
• p: Dichte [kg/m³] des trockenen Wasserspeichermaterials der Retentionsfassade
• W _SK: Wasserspeicherkapazität [Gew.-%].

For a retention facade according to the invention, a retention area factor can be introduced with $$\phi =\frac{m_{\mathit{water}}}{f_{\mathit{Total}}S\rho W_{\mathit{SK}}}$$

With

• m _water : amount of water to be stored [kg]
• F _Total : total (entire) facade area of the building [m ² ]
• S: Strength/thickness [m] of the retention facade
• p: Density [kg/m ³ ] of the dry water storage material of the retention facade
• W _SK : water storage capacity [% by weight].

The retention area factor indicates how much of the total façade area can be designed as a retention façade in order to enable sufficient rainwater retention.

For different scenarios of rainfall, water storage capacity and strength of the retention facade, it can then be calculated how much of the available facade area has to be designed as a retention facade in order to completely store the water that occurs.

The kinetics are not taken into account. Here it is assumed that with known water absorption coefficients of the water storage material used and directed and/or forced supply, the accumulating quantity can be stored in the facade.

Water absorption coefficients of known water storage materials are, for example, in the EP 2 904 895 B1 described. The revelation of the EP 2 904 895 B1 is hereby included in the disclosure content of the present description of the invention. However, the solution according to the invention is not in the EP 2 904 895 B1 described building materials and water absorption coefficients.

In the calculation of scenarios, it was found according to the invention that facades a few centimeters thick are also suitable for absorbing sufficient amounts of water. This differs from vertical greening concepts, which require a significantly greater minimum thickness to accommodate plant substrates.

The thickness of the retention arrangement, particularly in the case of a retention arrangement designed as a retention facade or retention wall, is preferably less than 15 cm, preferably less than 10 cm, particularly preferably between 2 cm and 5 cm. This ensures a sufficiently high water storage capacity.

For adequate rainwater retention, it can already be sufficient if the surface area of the retention facade in the total facade area of a building is less than 15%, preferably between 2% and 10%, particularly preferably between 5% and 8%.

The retention arrangement according to the invention can be self-supporting and/or designed as a load-bearing, stiffening or non-load-bearing wall or as a retaining wall of a building.

The retention arrangement can be formed by one or more components or can have them, which consist of the water storage material and/or can have this.

The retention arrangement can also have at least one monolithic, in particular cast, component and/or be formed by this.

The retention arrangement can also be formed by several components which are connected to one another in a modular manner and preferably flush with one another, it being possible for the components to be monolithic components.

Particularly preferably, the retention arrangement according to the invention can be designed as masonry, in particular as a solid wall, made of pressure-resistant components such as molded blocks, with the components preferably consisting of and/or being made from and/or having the water storage medium. The thickness of the molded blocks and/or the masonry can be less than 15 cm, preferably less than 10 cm, particularly preferably between 2 cm and 5 cm. This ensures a sufficiently high mechanical load-bearing capacity on the one hand and a sufficiently high water storage capacity on the other.

Components made of absorbent and liquid-storing materials are preferably used, more preferably based on mineral materials such as sand-lime brick. In principle, however, materials such as brick or aerated concrete are also possible, which should then be appropriately absorbent and liquid-storing and self-supporting. If mineral materials, such as sand-lime brick, are used, the series production of components as basic modules made of sand-lime brick can be carried out by selecting a suitable tool geometry without modifying the established manufacturing process. The individual sand-lime bricks can then be built into walls and large-area elements in a simple and established manner in the construction process.

At least one component or component of the retention arrangement according to the invention can have recesses and/or perforations, with perforations preferably being designed as through-openings and extending over the entire height or width or length of the component. The perforations can serve to conduct water within the retention arrangement and, in the combination of the components/components of the retention arrangement, can form a network of pipes, in particular a vascular system, for transporting water.

The proportion of recesses, cavities and perforations can be between 2.5% by volume and 75% by volume, preferably between 12.5% by volume and 55% by volume. Recesses, cavities and perforations can run perpendicularly to the bearing surface and/or horizontally to the bearing surface. Recesses, cavities and perforations can be round, square, pointed and/or have other cross-sectional geometries. Otherwise, recesses, cavities and perforations can be distributed symmetrically and/or differently on the surface of the component.

In an alternative embodiment, the retention structure according to the invention can also be designed as a free-standing retention structure. A preferably independent, free-standing retention body can optionally be arranged in front of a building wall and connected to it or, as a particularly sculptural spatial structure, can be arranged further away from a building and form a free-standing structure that serves to store water.

In relation to a building over which rainwater falls and is routed to the retention arrangement according to the invention, the retention arrangement can extend over at least one storey height of the building, preferably from the ground upwards over several floors, more preferably over all floors.

The water storage capacity of the retention arrangement can correspond to several times the amount of precipitation in heavy rain events per floor of a building with an average floor height of 3 m, so that even in heavy rain there is sufficient storage capacity to avoid flooding and damage caused by precipitation. For example, the water storage capacity of the retention arrangement per storey of a building with an average storey height of 3 m can correspond to a multiple of a precipitation quantity of 15 l/m ² h with a precipitation duration of 0.25 h to 0.5 h, in particular at least 1 times to 4-fold, more particularly 1-fold to at least 8-fold. With a rainfall of 40 l/m ² h, the water storage capacity of the retention arrangement per floor of the structure with an average floor height of 3 m can be 0.2 to at least 4 times, preferably 0.4 to at least 2 times , the amount of precipitation with a precipitation duration of 0.25 h to 0.5 h.

Depending on the design and the water storage material used, the maximum water volume that can be stored in the retention arrangement according to the invention can be at least 25%, preferably at least 40%, more preferably at least 50% of the total volume of the retention arrangement and/or the maximum water volume that can be stored in the retention arrangement can be less than 90% , preferably less than 80%, more preferably less than 75% of the total volume of the retention arrangement. The maximum volume of water that can be stored in the retention arrangement according to the invention is particularly preferably between 55% and 65% of the total volume of the retention arrangement. This ensures a high load-bearing capacity and mechanical stability of the retention arrangement.

The water storage material can have a pore structure for storing water and a maximum water storage capacity W _SK between 1% by weight and 200% by weight, preferably up to 150% by weight, more preferably in the range between 30% by weight and 150% by weight, and/or be swellable and then have a maximum water storage capacity of between 1% by weight and 20000% by weight, preferably 30% by weight and 5000% by weight , wherein the water storage capacity is based on the ratio of the maximum water mass that can be stored in the pore structure to the mass of the dry water storage material, in particular with a residual moisture content of the water storage material of less than 5% by weight, preferably from 2% by weight to 3% by weight.

The water storage capacity can also refer to the mass of the dry water storage material dried at 105 °C for 24 h as a reference basis.

mit

• m_Wasser: maximale, im Gleichgewicht speicherbare Wassermenge
• m_TR: trockene Masse des Wasserspeichermaterials (Restfeuchte 2 Gew.-% bis 5 Gew.- % und/oder getrocknet bei 105 °C für 24h).

The dry mass-related water storage capacity W _SK results from the following equation: $$W_{\mathit{SK}}=\frac{m_{\mathit{water}}}{m_{\mathit{TR}}}\left[\mathrm{in}\mathrm{\%}\right]$$

With

• m _water : maximum amount of water that can be stored in equilibrium
• m _TR : dry mass of the water storage material (residual moisture content 2% by weight to 5% by weight and/or dried at 105° C. for 24 h).

Typical values for the water storage capacity can be, for example, in the range between 2% by weight and 30% by weight if, for example, sand-lime brick is used as the water storage material.

The water storage material can particularly preferably be selected from the group of granules, in particular pumice granules and/or lava granules. The particle size of the granules can be between 0.5 and 5 mm, preferably up to 2 mm. Depending on the grain size, the bulk density of the granules can be between 700 and 1400 kg/m ³ , in particular between 850 and 1250 kg/m ³ .

Typical values for the water storage capacity can be, for example, in the range between 30% by weight and 150% by weight if, for example, pumice or lava granules are used as the water storage material.

When water is stored in a porous water storage material, the time it takes for the maximum water mass to be stored in the pore structure can be less than 1 hour, preferably less than 30 minutes, more preferably 15 minutes and/or more than 10 minutes.

In the case of a porous water storage material, water can escape from the retention arrangement by gravity, with at least 80% by weight, preferably at least 90% by weight, more preferably at least 95% by weight, of the water stored in the retention arrangement over a water retention period of at least 10 minutes, preferably at least 15 minutes, more preferably at least 20 minutes, particularly preferably at least one hour, are stored in the retention arrangement.

With a porous water storage material, water can escape from the retention arrangement for the most part through evaporation and/or when the switching temperature of a gel-type water storage material is exceeded, with the switching temperature preferably being in the range between 20°C and 40°C.

The residual moisture content of the retention arrangement after water has escaped can be less than 20% by weight, preferably less than 15% by weight.

The retention arrangement can consist of at least 50% by volume, preferably more than 75% by volume, more preferably more than 90% by volume, of the water storage material. This means that the majority of the retention arrangement is available for water storage.

The static load-bearing capacity of the retention arrangement can essentially be determined by the mechanical properties of the water storage material. The water absorption and storage are possible in particular without components or devices that increase the static load-bearing capacity of the retention arrangement, in particular no reinforcements made of steel or other materials are provided.

Water is preferably stored in a substantially evenly distributed manner within the retention arrangement according to the invention, in particular in a uniformly distributed manner arranged macroscopic cavities (openings) of the retention arrangement.

The retention arrangement can have at least one preferably self-supporting structural element, in particular designed as a bulk material cassette or lattice girder, for receiving a bulk of the water storage material. Particularly preferably, the structural element can have openings for ventilation, in particular for ambient air to flow through the bed, and/or for water to pass into and/or out of the bed. Liquid water can also drain or drip off via the openings when the water storage material is saturated.

Several structural elements can be combined to form a composite, in particular with the connected structural elements being set up and designed to conduct water and/or to transport water beyond the boundaries of the structural elements in the composite. For example, lines can be provided within the structural elements in order to enable water distribution in the individual structural elements and/or between the structural elements.

Particularly preferably, the construction element can be designed as a bulk material cassette and provided for receiving a bulk of the water storage material. The bulk goods cassette can preferably be in the form of a flat component with preferably planar, opposing delimiting and/or holding surfaces and a receiving area for the water storage material formed between them. In at least one delimiting and/or holding surface, preferably in a plurality of opposing delimiting and/or holding surfaces, openings for throughflow and/or for water to pass through can be provided in each case.

A bulk goods cassette can be formed by a frame that preferably runs around the circumference and that laterally delimits the receiving area. If necessary, openings can also be provided in the frame for ventilation and/or the passage of water. In this way, in particular, the dehumidification of the water storage material is supported by evaporation.

Limiting and/or holding surfaces can be formed by perforated plates or metal sheets or lattice arrangements that are held or fastened in particular to a frame of the bulk material cassette.

A number of cassettes can be connected to one another via frame structures, for example screwed together.

Lines can be routed across the frame boundaries inside the cassettes in order to enable water to be transported into the cassettes or into the water storage material contained in the cassettes and out of the cassettes or the water storage material.

The cassettes can be made of sheet metal or steel materials or, if necessary, also of plastic.

Alternatively, a lattice element can be provided for receiving a bulk of the water storage material, wherein the lattice element can have at least two opposing lattice areas between which a receiving area for the water storage material is formed. The water storage material is then also in the form of a bed within a lattice girder. The lattice areas can allow the lattice girder to be deformable in order to adapt it to the geometry of a building section, in particular due to a low bending stiffness of the lattice structure.

The retention arrangement according to the invention can have at least one recess, a cavity or a perforation for receiving the water storage material, with preferably at least one swellable water storage material being introduced into the recess, the cavity and/or the perforation and with the water storage material being more preferably dry State the recess, the cavity and / or the perforation only partially fills (= not completely). This takes into account the swelling behavior of swellable storage materials and prevents excessive mechanical loads due to the swelling pressure.

The water can also be fed in, at least periodically, independently of the rainwater connection, for example by connecting to a mains water network or by irrigation via an external water source using a hose, which enables active cooling of the environment at elevated temperatures in summer.

Water can be fed in via baffles, which, in addition to the water from the roof drainage, can also direct rainwater that reaches the retention arrangement.

The water can be fed in directly from the roof surface of the building without a rain gutter.

The water can be fed in by deflecting and/or collecting precipitation via precipitation collecting surfaces of awnings, foils, fabrics, photovoltaic elements, shading elements such as window shutters, cloths or the like, dew and fog nets, via funnel elements and movable components (kinetic architecture) and/or via guide plates take place, which are connected to the retention arrangement according to the invention and / or the structure according to the invention. The term "precipitation collection area of the building" is to be interpreted broadly and includes all areas of the building that are exposed to precipitation and from which rainwater is channeled directly or indirectly to and/or into the retention structure.

The water can also be fed into the retention structure via a central feed device, for example via a pipe or a pipeline system. Pipes can be designed to lengthen the route of the rainwater, for example, run in a meandering shape and/or have turns.

In principle, it is also possible to feed water into the retention structure from inside the house.

The water can be fed into the retention structure via a plurality of feed devices arranged evenly and/or unevenly distributed over the outer surface of the retention structure.

The water can also be fed in by connecting to a retention roof system or a green roof in order to drain and absorb excess water from retention roofs that have become full.

The water can also be fed in from below, for example from a water basin, by capillary forces of the water storage material.

Furthermore, water can be fed in from below the normal level or underground, for example from septic tanks or other underground collection tanks.

Feeding devices can apply water from the outside and/or from the inside over a large area and/or distributed at certain points, for example via baffles or nozzles, such as spray nozzles or slot nozzles. Feed devices can also be connected to a circulation system/pumping system.

A water distribution through structuring and/or channels applied from the inside and/or from the outside into and/or onto the surface of the retention arrangement, which can also be connected to one another, is advantageous. Structuring of the outer surfaces of the retention arrangement and/or channels can have different angles of inclination vertically and/or horizontally and thereby produce different water distribution speeds. Structures and/or channels can be symmetrically and/or asymmetrically wave-shaped. They can have undercuts, which also affects water line speed and water absorption.

The design of water-conducting and/or water-distributing structures and/or channels can be based on bionic methods, for example for imaging vascular systems. The term "vascular systems" is to be understood in particular as a system of water-conducting channels whose cross-sections decrease monotonically in the same direction of flow, for example from top to bottom in the retention arrangement or in the vertical direction, and/or where a certain amount of water in the water line in a direction of flow of the retention arrangement, for example from top to bottom or in the vertical direction, is initially distributed over a smaller number of flow channels with a larger cross section and, as the retention arrangement extends in the direction of flow, over a larger number of flow channels with smaller or equal flow cross sections. In other words, this means, for example, that a certain amount of water supplied to the retention arrangement is initially limited to fewer flow channels and with is distributed to more flow channels with increasing extension of the retention arrangement in the direction of flow.

Furthermore, the retention arrangement can have additional elements to promote water absorption and/or water conduction, further in particular through capillary forces, the additional element acting in the manner of a wick and supplying the water-storing material with the water to be absorbed. For example, fabric elements can be used as the wick.

The water storage material is preferably selected from the group of mineral materials, in particular sand-lime bricks, bricks or aerated concrete, and/or selected from the group of swellable materials. The retention structure can consist of the water storage material and/or have at least one such water storage material. A combination of different water storage materials is also possible.

Natural and/or synthetic polymers and/or mineral substances are suitable as swellable substances.

Polysaccharides selected from alginates, alginic acid, amylose, amylopectin, callose, carrageenan, cellulose, chitin, dextran, guluronic acid, inulin, laminarin, lichenin, pullulan, pustula, starch, starch derivatives, xanthan or mixtures thereof can be used as natural substances. As synthetic polymers z. B. materials from highly absorbent synthetic polymer, selected from polymers based on (meth) acrylate, poly (meth) acrylic acid and its salts, polyacrylamide, polyalcohols and copolymers of said synthetic polymers and other crosslinking and processing aids and property improvers. As mineral substances z. Example, clays such as bentonite or kalonite can be used. The substances are used as powders and/or granules in the particle size range of preferably 60 to 5000 μm. Powders and/or granules in the particle size range from 100 to 400 μm are preferably used.

example

Within the scope of the present invention, pumice granules and lava granules were used as water-storing materials for a retention arrangement according to the invention examined. Minimum and maximum amounts of rain per m ² floor area of a building arrangement or a building were assumed. The kinetics of the water absorption of the granules were determined using the method described above for determining the water absorption with free swelling in excess liquid. On the basis of the determined kinetics of the water absorption and using the bulk density, the respective volume of the retention arrangement was determined that is required to absorb and store a specific amount of rain occurring per minute of rain and m ² floor area of the building arrangement. Finally, a design calculation was carried out, on the basis of which building planning is possible.

Two rain scenarios were assumed, namely scenario 1 with 15 l/(m ² /h) and scenario 2 with 40 l/(m ² h). Pumice granules with a grain size of 0.5 to 2 mm and a relative mass increase in equilibrium after 24 hours of 145% by weight and pumice granules with a grain size of 1 to 5 mm with a relative mass increase in equilibrium after 24 hours of 65% by weight were examined %. In addition, lava granules with a grain size of 2 to 5 mm and a relative mass increase in equilibrium after 24 hours of 40% by weight were taken into account. The kinetics of water absorption (absorption measurement with free swelling, 20 °C, tap water, assumption of linear absorption kinetics in the range from 0 to 5 minutes) led to values of 0.95 kg water per kg dry pumice granules (0.5 to 2 mm) per minute; 0.57 kg water per kg dry pumice granules (1 to 5 mm) per minute and 0.5 kg water per kg dry lava granules (2 to 5 mm) per minute.

Bulk densities of the pumice granules (0.5 to 2 mm) of 950 kg/m ³ and of the pumice granules (1 to 5 mm) of 880 kg/m ³ were taken as a basis. The bulk density of the lava granules (2 to 5 mm) was taken into account as 1200 kg/m ³ .

From this, a design scenario for a building planner for a building with a floor area of 200 m ² and an estimated duration of a heavy rain event of 45 minutes and a rain volume for scenario 2 of 0.67 l/(m ² h) could be determined as an example, that to a volume of pumice granules (0.5 to 2 mm) of 6648 l, of pumice granules (1 to 5 mm) of 11962 l and of lava granules (2 to 5 mm) of 10000 l required to store rain per minute and square meter .

It was assumed that the retention order had not yet been 100 percent filled in the design calculation. The maximum water absorption capacity is then determined by the maximum storage capacity of the granules.

Fign. 1A-C

eine Konzeptdarstellung, die die Auswirkung von Retentionsfassaden zur Verringerung des Überflutungsrisikos von urbanen, starkverdichteten Quartieren im Rahmen von Starkregenereignissen zeigt,

Fig. 2

eine schematische Darstellung der Verwendung von Retentionsfassaden an Gebäuden,

Fign. 3-5

verschiedene Ausführungsformen von gelochten Bauelementen zur Errichtung einer erfindungsgemäßen Retentionsanordnung,

Fig. 6

eine schematische Darstellung eines Bauelementes für eine erfindungsgemäße Retentionsanordnung mit einem Hohlraum zur Aufnahme eines quellfähigen wasserspeichernden Materials in waagerechter Ausführung im trockenen Zustand des quellfähigen Materials,

Fig. 7

das Bauelement aus Fig. 6 im aufgequollenen Zustand des wasserspeichernden Materials,

Fig. 8

eine schematische Darstellung eines Bauelementes für eine erfindungsgemäße Retentionsanordnung mit mehreren quer verlaufenden Hohlräumen mit quellungsfähigem Material in waagerechter Ausführung,

Fig. 9

ein Bauelement mit senkrecht verlaufenden Hohlräumen, in die ein quellungsfähiges wasserspeicherndes Material eingebracht ist, im nicht-gequollenen Zustand des wasserspeichernden Materials,

Fig. 10

das in Fig. 9 gezeigte Bauelement im aufgequollenen Zustand des wasserspeichernden Materials;

Fig. 11

ein Beispiel für die mit Retentionsfassaden erreichbaren Niederschlagsspeichermengen,

Fig. 12

eine schematische Darstellung eines Kassettenelements zur Aufnahme eines Wasserspeichermaterials für eine erfindungsgemäße Retentionsanordnung;

Fig. 13

eine schematische Darstellung mehrerer Kassettenelemente der in Fig. 12 gezeigten Art im Verbund und

Fig. 14

eine schematische Darstellung einer Gitterstruktur zur Aufnahme eines Wasserspeichermaterials zur Verwendung für eine erfindungsgemäße Retentionsanordnung.

The invention is described below by way of example with reference to the drawing. Show in the drawing

Figs. 1A-C

a conceptual representation that shows the effect of retention facades to reduce the risk of flooding in urban, densely populated neighborhoods in the context of heavy rain events,

2

a schematic representation of the use of retention facades on buildings,

Figs. 3-5

various embodiments of perforated components for establishing a retention arrangement according to the invention,

6

a schematic representation of a component for a retention arrangement according to the invention with a cavity for receiving a swellable water-storing material in a horizontal design in the dry state of the swellable material,

7

the component off 6 in the swollen state of the water-storing material,

8

a schematic representation of a component for a retention arrangement according to the invention with a plurality of transverse cavities with swellable material in a horizontal design,

9

a building element with vertically running cavities, into which a swellable water-storing material is introduced, in the non-swollen state of the water-storing material,

10

this in 9 component shown in the swollen state of the water-storing material;

11

an example of the amounts of precipitation storage that can be achieved with retention facades,

12

a schematic representation of a cassette element for receiving a water storage material for a retention arrangement according to the invention;

13

a schematic representation of several cassette elements in 12 shown type in combination and

14

a schematic representation of a lattice structure for receiving a water storage material for use in a retention arrangement according to the invention.

Based on Figures 1A to 1C measures for rainwater retention and flood prevention in the event of heavy rain events are shown schematically. Figure 1A shows a schematic of an urban, densely populated district with various buildings 1. Due to a high degree of sealing, a lower infiltration potential and high soil compaction, there can be considerable problems with the drainage of rainwater, especially during heavy rain events, combined with the risk of flooding. this is in Figure 1A characterized by a flood height X shown schematically.

Figure 1B shows that in the area of rainwater retention, retention roofs 2 can be used in urban areas to retain rainwater and reduce the risk of flooding. this is in Figure 1B shown by a schematically shown lower flood height XY in the case of heavy rain events. Retention roofs 2 alone, however, are not suitable for completely eliminating the risk of flooding due to the high amounts of precipitation during heavy rain events.

Figure 1C shows the effect of retention facades 3 on the risk of flooding of urban quarters in the context of heavy rain events. Retention facades 3 are vertical retention arrangements provided on the lateral building shell or lateral outer skin of buildings 1 for water retention through water absorption and water storage. How out Figure 1C results, such retention facades 3 can have sufficiently high storage capacities per building 1 with a suitable design and through the use of suitable water storage materials in order to even completely absorb the water quantities occurring during heavy rain and thus the risk of flooding to lower to zero. In this case, the storage capacity per building for precipitation water can increase essentially linearly with increasing facade height or increasing number of storeys of the building 1 with a suitable design of the retention facades 3 . Retention facades 3 can be formed by building elements in front of and/or suspended from one of the building facades, in particular in a modular design, or also by independent building walls of a building 1.

Retention facades 3 are preferably formed by self-supporting wall or structural element systems, which can consist of mineral substrates, for example, from which complete walls can be erected, which are statically dimensioned and inherently water-storing at the same time.

The water stored in the retention facade 3 can be made available to the buildings 1 for use again, either as process water by being discharged from the water storage medium or indirectly by water evaporation and the associated cooling with an associated improvement in the microclimate.

As in 2 shown, depending on the type of construction, buildings 1 can have retention facades 3 on two opposite sides of the building (in the case of buildings 1 arranged in a building complex, such as terraced houses, 2 , below) or on all sides of the building (in the case of free-standing buildings 1, such as single-family houses or halls, 2 , below).

As in the Figs. 3 to 5 shown, retention facades 3 can be formed by free-standing, load-bearing or non-load-bearing retention walls, which can be designed as masonry. Such retention walls consist of or have components 4, which can be designed as individual stones or as plan stones. In principle, known production methods for stone production from sand-lime brick or for brick production and thus established production processes can be used to produce these components 4 . The water storage capacity of the building materials used can be adjusted by adapting the recipe and can therefore be optimized in relation to the application. Typical water storage capacities, defined as the water mass absorbed by the water storage material or the building element in relation to the dry mass of the water storage material (at a residual moisture content between 2% and 5%) can be in the range between preferably 5% to 30%, for example 20%, with the time it takes to reach the maximum water storage capacity being less than 1 hour, preferably less than 30 minutes, in particular 15 minutes or less .

The use of caverns, undercuts, water-conducting structures and/or different feed points can promote optimal, fast and efficient water distribution in the retention wall. By connecting to a roof and/or building drainage system of a building 1, it can be ensured that, in addition to the direct absorption of rain, preferably essentially all of the water occurring on the building 1 during a heavy rain event is fed into the retention wall.

When using porous building materials, the existing pore system of the building material also enables water to be discharged from the building elements 4 by gravity. If more water is introduced than can be stored via the pore system, the water exits in the lower area of the building elements 4 and can thus be used, for example, as service water in building 1 or used to water surrounding green areas.

Figs. 3 to 5 also show that the components 4 can be perforated, with perforations 5 being able to run in particular perpendicularly to the bearing surface in order to promote water conduction and distribution within the components 4.

Instead of perforations 5, other openings can also be provided in the components 4 in order to create cavities in which, for example, a swellable water storage material 6 is introduced. The swellable water storage material 6 can serve to store water in addition to the building material from which the components 4 are made. In principle, it is also possible for water to be stored only via a swellable water storage material 6 . As can be seen from the Figs.6 and 7 results, the swellable water storage material 6 only partially fills the perforation 5 present in the component 4 in the dry, non-swollen state, so that sufficient empty volume remains to allow the water storage material 6 to swell. In the fully swollen state, the water storage material 6 can then completely fill out the perforation 5 . The degree of filling of the perforation 5 with the water storage material 6 is to be dimensioned in such a way that it is in the swollen state of the water storage material 6 there is no component-endangering mechanical stress due to the swelling pressure.

8 shows that horizontal cavities can also be filled with swellable material in order to provide a sufficiently high water storage capacity.

the Figs. 8th and 9, 10 show components 7 with swellable water storage material 6 with horizontal ( 8 ) and vertical ( Figures 9, 10 ) Openings or perforations 5, wherein, in the case of vertical perforations 5, the swellable water storage material 6 is arranged in a dry state in the region of the perforations 5 lying vertically below ( 9 ) and expands upwards when it swells, so that in the fully swollen state the cavities are essentially completely filled by the water storage material 6 ( 10 ).

The vertical surfaces available on the buildings have a high potential for water storage. 11 shows an example of the water storage capacity for vertical retention facades 3. A building with a floor area (roof area) of 120 m ² is considered as an example, with a building width of 8 m and a building length of 15 m. With different heavy rain events (15 and 40 l/ m ² h) total water quantities of 450 to 2,400 l fall over the roof surface with different periods of heavy rain (e.g. 0.25 h and 0.5 h).

Depending on the building situation (free-standing or in a group), the storey height (taken as an example: 3 and 6 storeys, with a storey height of e.g. 3 m) and taking into account unusable window areas, different sized areas of the building facade can be used in building 1 as retention facades 3 train or use.

If these parameters are taken into account and the retention facades 3 are formed by, for example, 10 cm thick retention walls, for example based on sand-lime brick with a water storage capacity of 12% based on the dry mass with a water absorption period of more than 0.5 h, the building has storage quantities of 3,291 l to 10,091 I water, which is already provided in the event that three floors and two retention facades 3 (building in association), approx. 37% above the maximum water volume of 2,400 l.

How out 11 further results, 1 retention facades 3 can be formed by corresponding retention walls in free-standing buildings 1 on all four vertical outer sides of the building. Only the roof areas are not designed to absorb and store water. The storage volume for rainwater could be increased by appropriate roof greening or roof retention areas.

Furthermore, it cannot be ruled out that water can also be supplied to the retention facades 3 via water pipe networks, possibly also by water being fed in from inside the building 1 or from below from water basins or septic tanks, for example in order to improve the microclimate through evaporation of the stored water and evaporative cooling to influence.

In 12 a cassette element 8 is shown for receiving a water storage material for use in a retention arrangement. The cassette element 8 is formed by a frame 9 and two perforated plates 10, with a receiving area for receiving the water storage material being formed between the perforated plates 10. The perforated plates 10 have openings 11 via which the water storage material can be dehumidified once the water has been absorbed. The dehumidification preferably takes place via both flat sides of the cassette element 8 . The openings 11 can also be used to drain accumulating precipitation water out of the cassette element 8 . What is not shown is that the supply of precipitation water can take place via lines that lead into the heat storage material.

13 shows schematically the arrangement of several cassette elements 8 from 12 in a union. Due to the modular design, retention volumes and areas of different sizes can be easily produced.

14 shows a lattice structure 12 designed and set up to accommodate a water storage material for use in a retention arrangement for retaining rainwater. The lattice structure 12 can, as in 14 shown, have a non-planar surface profile, the contour or-das Surface profile of a building structure, for example, adapted to the contour of the outer facade of a building.

Reference list:

1

building

2

retention roof

3

retention facade

4

component

5

perforation

6

water storage material

7

component

8th

cassette element

9

frame

10

perforated plate

11

opening

12

lattice structure

Claims (14)

Retention arrangement for retaining precipitation water, in particular in the event of heavy rain events in urban, highly densely built-up areas, having a porous and absorbent and/or swellable water storage material, the retention arrangement being a particularly vertical retention facade (3) and/or a particularly vertical retention wall of a building, such as a Residential or commercial building (1), an industrial hall or noise barrier or bridge or the like, or is designed as a free-standing, essentially vertical retention structure, the retention arrangement being connected to a building arrangement for draining rainwater from at least one roof and/or facade surface of the Building arrangement for retention arrangement and for at least temporary storage of precipitation water in the retention arrangement, and wherein the retention arrangement for water absorption and water storage on the base area of the Ge building layout and a minimum amount of water based on precipitation duration of 10 l/(m ² h) to 50 l/(m ² h), preferably 15 l/(m ² h) to 40 l/(m ² h), is designed and set up a floor area of the building arrangement of at least 50 m ² , preferably at least 100 m ² , particularly preferably at least 200 m ² , and with a precipitation period of at least 0.25 h, more preferably at least 0.5 h, particularly preferably 0, 75 h. Retention arrangement according to Claim 1, characterized in that the retention arrangement is constructed and set up for water absorption of 0.1 to at least 2.0 kg _water /(kg _WSM,dr.min ), preferably 0.5 to at least 1.0 kg _water /(kg _{WSM, dry} min),
With: $${\mathrm{kg}}_{\mathrm{water}}=\mathrm{recorded}\mathrm{water\; mass}\mathrm{in}\left[\mathrm{kg}\right]\mathrm{and}\mathrm{With}$$

$${\mathrm{kg}}_{\mathrm{WSM},\mathrm{tr}.}=\mathrm{Dimensions}\mathrm{of}\mathrm{dry}\mathrm{water\; storage\; material}\mathrm{.}$$

Retention arrangement according to claim 1 or 2, characterized in that a fluidic and / or line-bound connection to a roof and / or building drainage of the structure of the building arrangement for directed, in particular line-guided, and / or controlled and regulated feeding on and / or precipitation water accumulating on the structure is provided in the retention arrangement. Retention arrangement according to one of the preceding claims, characterized in that at least part of a building facade is formed by the retention arrangement. Retention arrangement according to one of the preceding claims, characterized in that the retention arrangement is self-supporting and/or that the retention arrangement is designed as a load-bearing, stiffening or non-load-bearing wall or as a retaining wall of a building. Retention arrangement according to one of the preceding claims, characterized in that the retention arrangement is designed as masonry, in particular as a solid wall, from pressure-resistant components (4), such as molded blocks, with the components (4) preferably consisting of the water storage medium and/or of it are made and / or have this. Retention arrangement according to one of the preceding claims, characterized in that the retention arrangement is designed as a free-standing retention structure. Retention arrangement according to one of the preceding claims, characterized in that the water storage material has a pore structure for storing water and a maximum water storage capacity of between 1% by weight and 200% by weight, preferably up to 150% by weight, more preferably in the range between 30 % by weight and 150% by weight, and/or that the water storage material is swellable and has a maximum water storage capacity of between 1% by weight and 20000% by weight, preferably 30% by weight and 5000% by weight, has, in each case based on the ratio of the maximum water mass that can be stored in the pore structure to the mass of the dry water storage material. Retention arrangement according to one of the preceding claims, characterized in that the water storage material is selected from the group of granules, in particular pumice granules and/or lava granules. Retention arrangement according to one of the preceding claims, characterized in that the retention arrangement has at least one preferably self-supporting structural element, in particular designed as a bulk material cassette or lattice girder, for receiving a bed of the water storage material, the structural element preferably having openings for ventilation, in particular for ambient air to flow through the bed, and/or for water to pass into the bed and/or out of the bed. Retention arrangement according to claim 10, characterized in that several structural elements are combined to form a composite. Retention arrangement according to Claim 10 or 11, characterized in that a bulk material cassette is provided for receiving a bulk of the water storage material, the bulk material cassette preferably being a flat component with preferably planar opposing delimiting and/or holding surfaces and a receiving area for the water storage material formed in between has, wherein, preferably, in at least one delimiting and/or holding surface, preferably in both delimiting and/or holding surfaces, openings for throughflow and/or for the passage of water are provided. Retention arrangement according to Claim 10, characterized in that a lattice girder is provided for receiving a bed of water storage material, the lattice girder having at least two opposing lattice areas between which a receiving area for the water storage material is formed. Building, such as a residential or commercial building (1), industrial hall, noise protection wall, bridge or the like, with at least one retention arrangement connected to the building or free-standing according to one of the preceding claims, wherein the retention arrangement is preferably attached to a precipitation collection surface of the building, in particular to a roof and/or building drainage of the building, and/or is connected to a mains water network.

Images